This invention relates generally to the recovery of quaternary ammonium salts from aqueous solutions and more particularly to the recovery of quaternary ammonium salt, phase transfer catalysts from reaction mixtures resulting from the alkylation of cyclopentadienes.
The preparation of monosubstituted cyclopentadiene derivatives by condensation with corresponding halogen compounds such as alkyl halides in the presence of a condensing agent such as aqueous alkali metal hydroxide and small amounts (below about 0.1 mole per mole of cyclopentadiene) of quaternary ammonium compounds, which catalyze the reaction, is described in Polish Patent 55,571.
I have found an effective method for recovering the catalyst which permits its reuse and also avoids its discharge in the aqueous waste stream from the reaction.